It appears the women were brought together by mutual respect and maturity united hate for fellow 90210 actress Tiffani Thiessen!

Thiessen confirmed the new rivalry during a recent interview with Howard Stern. Kelly Kapowski Tiff explained that for years she and Jennie had been BFFs. They were in each other's weddings, she even "saw her [Jennie] give birth to her first child" — the whole nine yards!

But, like all things 90210. their friendship came to a dramatic end!

Thiessen confesses:

"We had a falling out and we grew apart. I was the one who was hurt, let's just say that. I was the one who was hurt. It's funny, our relationship started really rough and ended the way it started."

Poor girl!

Despite being wronged, Thiessen says the whole feud is, "Water under the bridge. I've moved on. I wish her well."

How does Garth feel about all this??

There's a chance her public split from Peter Facinelli has given her some perceptive on needless cat fighting… but we aren't betting on it!

Ever since Christina Aguilera and her husband, Jordan Bratman, split earlier in the year, the singer has definitely displayed some erratic behavior - including her new relationship with boy toy PA Matt Rutler, a reported freak out on Burlesque co-star Julianne Hough, and getting so drunk at Jeremy Renner's birthday that she allegedly passed out in his bed - that many are comparing to Britney Spears' nervous breakdown in 2007!

And while pals are suggesting that it hasn't gotten that serious, they aren't denying that she's AActing out - and it's even starting to affect her appearance!

Sources reveal:

"It’s beginning to take a toll on her looks. Youth can only carry you so far. Xtina is starting to look haggard! But [her divorce] it’s got her acting too crazy. After all, she is the mother of a 3-year-old little boy [son Max]. She needs to act more responsibly."

Agreed!

We can't even begin to imagine how difficult divorce must be, but we've seen many go down this road before, and believe us - it's not pretty!

You've had your post-break-up grace period, bb!

Now it's time to get your shit together - before people start becoming concerned over Max's well-being!